2 Racing deckcollars: Both have an oval and tapered inner diameter. The oval inner diameter allows the maximum fore/aft play and minimum side play. The tapered inner diameter allows the mast to be raked. 4 countersunk mounting holes. Hole size in deck : Ø 57 mm EX1210 has a separate sleeve which is fitted around the mast at deck level and protects the mast from wearing. EX1210